• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.331-334
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• 2002

Culture conductivity and on-line NADH fluorescence were used to measure cellular growth in plant cell suspension cultures of Podophyllum hexandrum. An inverse correlation between dry cell weight and medium conductivity was observed during shake flask cultivation. A linear relationship between dry cell weight and culture NADH fluorescence was obtained during the exponential phase of batch cultivation In a bioreactor under the pH stat (pH 6) conditions. It was observed that conductivity measurement were suitable for biomass characterisation under highly dynamic uncontrolled shake flask cultivation conditions. However, if the acid/alkali feeding is done for pH control the conductivity measurement could not be applied. On the other hand the NADH fluorescence measurement allowed online-in situ biomass monitoring of rather heterogenous plant cell suspension cultures in bioreactor even under the most desirable pH stat conditions.

• 대한지리학회지
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• 제39권3호
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• pp.444-456
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• 2004

최근 GIS 분야에서는 GIS와 동적 프로세스 모델링에 기반한 셀룰라 오토마타(CA)의 결합을 통한 공간모델링 연구가 활발히 진행되고 있다. 그러나 선행 연구에서의 CA 모델링은 해결하고자 하는 문제의 핵심이 되는 규칙을 찾아내는 기능은 제공하지 못하고 있다. 본 연구에서는 GIS와 지식 발견 기법을 이용하여 공간 연관규칙을 추출하는 방법론을 제시하고 실제 사례에 적용하였다. 이러한 방법론의 제시는 CA 모델링의 기능을 더욱 향상시킬 것으로 기대된다. 또한 본 연구에서 사례로 적용한 도시지역 확장 외에 다양한 문제에 대한 활용이 가능할 것으로 판단된다.

• 한국환경과학회지
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• 제11권10호
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• pp.1069-1074
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• 2002

The growth and heavy metal experiments revealed oppositive interactions between toxic metals(Zn and Cd) and Mn when the coastal diatom T. pseudonana were used. Cd and Zn inhibited the algal growth rate only at low Mn ion concentrations and this effect could be accounted for an inhibition of cellular Mn take by the toxic metals. Mn and Zn inhibited cellular Cd take and this indicated a reciprocal effects among the metals with respect to metal take. Saturation kinetics modeling of the take data was consistent with two metals competing with each other for binding to the Mn take system and with both Cd and Mn being transported into the cell by that system. Mathematical modeling of Mn and Cd take data revealed evidence fur a Cd efflux system.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.266.2-266.2
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• 2013

According to advanced nanotechnology, the nanostructured materials with various kinds and shape are synthesized easily or produced by process. Recently, researches about interaction between the nanostructured materials and biological system have been progressed actively. The surface topography may influence cellular responses, for example cell adhesion, cell morphology. In this work, we synthesized vertically aligned silicon nanowires (SiNWs) on the Au-covered Si(111) wafer by chemical vapor deposition (CVD) method. We accomplished to control of the SiNWs diameter by regulating thickness of Au film such as 1 nm and 10 nm. These substrates did not isolate cells and just provided surface topography for cell culture. Human Embryonic Kidney 293T cells (HEK 293T cells) were cultured on these substrates for 2 days. We studied the nanotopographical effects on cell morphology, adhesion, and growth which are evaluated on each SiNWs substrate comparing bare glass as control.

• 대한핵의학회지
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• 제36권4호
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• pp.209-223
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• 2002

By considering the biological properties of a tumor, it should be possible to realize better results in cancer therapy. PET imaging offers the opportunity to measure tumor growth non-invasively and repeatedly as an early assessment of response to cancer therapy. Measuring cellular growth instead of energy metabolism showed offer significant advantages in evaluating therapy. Thymidine and its derivative nucleoside compounds can be changed to mono, di- and tri- phosphate compounds by thymidine kinase and then be incorporated into DNA. Their bindings are increased in highly proliferating cells due to the high DNA synthesis rate. To evaluate cell proliferation, many kinds of thymidine and uridine derivatives have been labeled with positron emitter and radioactive iodine. Compared to radiopharmaceuticals which have radioisotope labeled base ring such as pyirmidine, the radiopharmacuticals which have radioisotope labeled sugar ring are more stable in vivo and have metabolic resistance. The biological properties such as DNA incorporation ratios are highly dependent on their chemical structures and metabolic processes. This overview describes synthesis of radiopharmaceuticals and their biological properties for imaging of tumor cell proliferation.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.171-180
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• 2021

Caffeine, a methylxanthine analog of purine bases, is a compound that is largely consumed in beverages and medications for psychoactive and diuretic effects and plays many beneficial roles in neuronal stimulation and enhancement of anti-tumor immune responses by blocking adenosine receptors in higher organisms. In single-cell eukaryotes, however, caffeine somehow impairs cellular fitness by compromising cell wall integrity, inhibiting target of rapamycin (TOR) signaling and growth, and overriding cell cycle arrest caused by DNA damage. Among its multiple inhibitory targets, caffeine specifically interacts with phosphatidylinositol 3-kinase (PI3K)-related kinases causing radiosensitization and cytotoxicity via specialized intermediate molecules. Caffeine potentiates the lethality of cells in conjunction with several other stressors such as oxidants, irradiation, and various toxic compounds through largely unknown mechanisms. In this review, recent findings on caffeine effects and cellular detoxification schemes are highlighted and discussed with an emphasis on the inhibitory interactions between caffeine and its multiple targets in eukaryotic microorganisms such as budding and fission yeasts.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.327.3-328
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• 2002

Transforming growth factor-${\beta}$ (TGF-${\beta}$), a hormonally active polypeptide found in normal and transformed tissues. regulates cellular growth and phenotyphic plasticity. We have previously shown that H-ras. but not N-ras. induces invasive phenotype in MCF10A human breast epithelial cells. In this study. we wished to examine the effect of TGF-${\beta}$ on H-ras-induced invasion and motility in MCFI 10A cells by performing in vitro invasion assay and wound migration assay. (omitted)

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.623-634
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• 1995

Periodontitis is characterized by gingival inflammation and results in periodontal pocket formation with loss of the supporting alveolar bone and connective tissue around the teeth. Therapeutic modalities should therefore aim not only at eliminating the gingival inflammatory process and preventing the progression of periodontal disease but also at reestablishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, progenitor cells must migrate to the denuded root surface, attach to it, proliferate and mature into an organized and functional fibrous attachment apparatus. Likewise, progenitor bone cells must also migrate, proliferate, and mature in conjunction with the regenerating periodontal ligament. Significant advances have been made during the last decade in understanding the factors controlling the migration, attachment and proliferation of cells. A group of naturally occuring molecules known as polypeptide growth factors in conjunction with certain matrix proteins are key regulators of these biological events. Of these, the fibroblast growth factor(FGF), platelet-derived growth factor(PDGF) , insulin like growth factor(CIGFs), transforming growth factor(TGFs), epidermal growth factor(EGF) and bone morphogenetic growth factor(BMPs) apper to have an important role in periodontal wound healing. The purpose of this study was to determine the effects of BMP on periodontal ligament cells. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Cultured periodontal ligament cells were treated with BMP. Cellular activities were determined by MTT(3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and ALP(alkaline phosphatase) activity. The results were as follows ; Regardless of cultured time, cellular activities were stimulated by BMP. Also, BMP greatly increased alkaline phosphatase(ALP) in periodontal ligament cells. These results suggest that BMP not only have no cytotoxic effect on periodontal ligament cells, but also have osteogenic stimulatory effect on periodontal ligament cells.

• Environmental Analysis Health and Toxicology
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• 제23권2호
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• pp.101-112
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• 2008

Effects of various concentrations of copper on growth change of blue-greenalgae Anabaena flos-aquae were studied. There was significant differences among cultures treated with various concentrations of copper in growth of algae with parameters of cell numbers, specific growth rate (SGR) and chlorophyll contents. Algal growth and SGR were inhibited on by effect of various concentrations of copper more than without copper (ANOVA, F=34.69 p<0.001, F=114.89, p<0.001). The SGRs of various concentrations of copper in media were higher than without copper on 8 days after copper treated. The mean of chlorophyll contents was 1.978 ${\mu}g{\cdot}mL^{-1}$ and 1.648 ${\mu}g{\cdot}mL^{-1}$, respectively, while those of algae in culture without copper was 3.179 ${\mu}g{\cdot}mL^{-1}$ (ANOVA, F=153.74, p<0.001). The cellular morphology was different between media of which copper treated and without copper. The colony of algae in media which copper treated was shorter than without copper. Effects of various concentrations of copper on growth change of blue-green-algae Anabaena flos-aquae occured variety changes of parameters of cell numbers, specific growth rate (SGR), chlorophyll contents and cellular morphology on growth of algae.

• ALGAE
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• 제28권2호
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• pp.193-202
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• 2013

Nitrogen availability and cell density each affects growth and cellular astaxanthin content of Haematococcus pluvialis, but possible combined effects of these two factors on the content and productivity of astaxanthin, especially under outdoor culture conditions, is less understood. In this study, the effects of the initial biomass densities IBDs of 0.1, 0.5, 0.8, 1.5, 2.7, 3.5, and 5.0 g $L^{-1}$ DW and initial nitrogen concentrations of 0, 4.4, 8.8, and 17.6 mM nitrate on growth and cellular astaxanthin content of H. pluvialis Flotow K-0084 were investigated in outdoor glass column photobioreactors in a batch culture mode. A low IBD of 0.1 g $L^{-1}$ DW led to photo-bleaching of the culture within 1-2 days. When the IBD was 0.5 g $L^{-1}$ and above, the rate at which the increase in biomass density and the astaxanthin content on a per cell basis was higher at lower IBD. When the IBD was optimal (i.e., 0.8 g $L^{-1}$), the maximum astaxanthin content of 3.8% of DW was obtained in the absence of nitrogen, whereas the maximum astaxanthin productivity of 16.0 mg $L^{-1}\;d^{-1}$ was obtained in the same IBD culture containing 4.4 mM nitrogen. The strategies for achieving maximum Haematococcus biomass productivity and for maximum cellular astaxanthin content are discussed.